Until May 24, you can get a medium coffee and a glazed donut from this sweet spot — totally free of charge.
The company specified this deal is "Valid in participating Canadian stores only. Not valid w/other offers. MONDAYS ONLY."
And there's a limit of one coffee and one donut per customer, which means you can't be greedy.
Instead, you just have wait until the next week to go back and get your free items again.